Interesting if true: fuel from air

[james_davis_nicoll]

A British firm based on Teeside says it's designed revolutionary new technology that can produce petrol using air and water.

Seriously, BBC? "It's" for possessive it? Never snark before coffee.

Presumably there's some kind of energy source, assuming they have not gone the heart of a forsaken child route. Also

Air Fuel Synthesis in Stockton-on-Tees has produced 5 litres of petrol since August, but hopes to be in production by 2015 making synthetic fuel targeted at the motor sports sector.

it's not quite ready for prime time.

This is a way of moving energy from energy rich regions to energy poor ones.

(usual bbc & technology disclaimer: they still do puff pieces on Moller)

Comments

[mad-troll.livejournal.com]

Isn't that it's as in it has? I mean, if the main verb's not there, then where is it?

[ellarien]

It's for "it has," I think.


... I wonder if something like this would be one way of solving the "no way to store energy" problem with wind etc, if the efficiency isn't too dismal.

[nojay.livejournal.com]

There are plenty of ways to store energy from intermittent and cyclical sources like wind, solar etc. They all cost money and waste some of the energy stored. For example the Dinorwic pumped-storage station in south Wales cost over 1.3 billion dollars US (in 2012 dollars) to build, can store about 10GWh max (or half a day's output from a single nuclear reactor) and returns about 66% of the energy input i.e. using 1GWh to pump water up to the top reservoir will return about 660MWh when the stored water is released back down the mountainside through the turbines.

[neowolf2.livejournal.com]

More to the point: converting electrical energy to chemical energy of fuel is quite uneconomical, be that fuel hydrogen, some hydrocarbon, etc. Fuels derived from other reduced carbon sources are much less expensive.

Unless highly penalized by law, we'll be seeing people mining the tropical forests for biomass, or doing in situ gasification of deep coal deposits unmineable by convention techniques, all to convert to fuel, before we see large scale electro-synthetic fuel production.

[resonant.livejournal.com]

At a guess, it'd be similar to Robert Zubrin's method of fueling a Mars return vehicle using the local atmosphere. Hideously inefficient, but cheaper than importing the fuel.

It might have a use on nuclear-powered aircraft carriers to make jet fuel.

[nojay.livejournal.com]

A carrier's reactor(s) can't make liquid fuels faster than the planes would burn it. Gasoline or other hydrocarbon fuels are very energy dense in terms of mass and volume, and being liquid they're easy to pump and meter unlike the other common carbon-based fuel, coal.

Lessee, a litre of JP-4 contains about 35MJ or about 10kWh. US carrier reactors produce about 190MW at full chat (twin A4W reactors for the Nimitz class) so at an optimistic 33% conversion efficiency and dedicating one reactor's output to fuel production they could make about 3300 litres of JP-4 an hour. An F/A-18 burns about 10,000 litres of fuel an hour in normal flight so it would need three hours production from one dedicated reactor to fuel one plane for one operational cycle (takeoff, patrol, landing). Nimitz-class carriers carry 80-90 planes.

[krfsm.livejournal.com]

On the other hand, they can run the production when the planes aren't flying to build up stores, and while they're flying to extend operational cycle capacity (even if only slightly).

[derekl1963.livejournal.com]

As the other gentleman pointed out - they can run the reactors when the planes aren't flying. They can also, in future carriers, install additional or uprated reactors. Even the reactors on existing carriers are far larger than needed for cruising during non flight ops as they're sized to provide flank speed during full launch ops (consuming mongo amounts of steam for the cats) with a significant margin. So, during normal cruising, I wouldn't be surprised if you couldn't dedicate around 1.5 (or more) reactors to fuel production.

The downside of course is that will mean expending EFPH (Effective Full Power Hours - a measure of how much "gas" is in the carrier's nuclear "tank") at a prodigious rate. This is already a problem, as the OPTEMPO of the last decade has considerably exceeded the estimates used to determine the lifetime of the carrier's cores.

[james-angove.livejournal.com]

You numbers for hornet fuel consumption can't be right. The F/A-18E has internal fuel storage for ~14000lbs of fuel. This is all back of the envelope, since I don't know how my JP4 ways, and it is 3 in the morning, but if it were water, 10,000 liters would way around ~20000 lbs.

I know for sure that the loiter time for a F/A-18 is longer than 45 minutes.

[(Anonymous)]

Accurately priced fossil carbon sources are too expensive to use at all. (Really. We're halfway to "we're absolutely sure agriculture breaks past this point"; getting there has a price tag of "industrial civilization".)

Recent discoveries that you can change, at a very teeny scale, the properties of space-time in ways that influence chemical reactions, suggest that there's probably a much more efficient way to make simple molecules than we have now.

Given that, we should be looking at NH3, rather than a hydrocarbon. Need it anyway for agriculture, and a combination of ammonia and alkaline fuel cells gets us off the ~25% efficiency cap for internal combustion engines.

-- Graydon

[doc-lemming.livejournal.com]

25%? I speak in ignorance, but I thought the Carnot Cycle limit, at least the theoretical one, was higher? Or is there a different efficiency cap that I'm ignorant of?

[neowolf2.livejournal.com]

Large diesel engines can be much better than 25% efficient.

Also, combustion turbines are internal combustion engines, and can be quite efficient, especially with combined cycle.

[(Anonymous)]

And neither approach works well for cars or trains or lawnmowers or portable generators or indeed most things we currently use fossil carbon and internal combustion engines for, but the simple expedient of being too stonking big.

-- Graydon

[resonant.livejournal.com]

I am eagerly watching the progress of thermoelectric materials. If we can get something with the efficiency of bismuth telluride, but without the toxicity, we can turn every IC radiator and exhaust pipe into a source of electricity. Instead of using engine power to run the alternator, cars will charge their battery from engine waste heat. Just like the bottoming cycle from a combined cycle setup, but with no moving parts.

[(Anonymous)]

The theoretical limit is higher; there are great big (more-than-house-sized) marine diesels that approach the theoretical limit and have operating efficiencies around 40%.

But the great majority used for transport purposes are running about 25%. And that matters, because it affects how you look at system efficiency for the synthetic fuel full pathway.

(50% synthesis efficiency with 25% combustion efficiency is a worse place to be than 25% synthesis efficiency and 80% conversion efficiency, for example, presuming you're powering the synthesis from the same source. And it's the total pathway efficiency that matters.)

-- GRaydon

[neowolf2.livejournal.com]

Those marine diesels are cool. Built at the shipyard, they have cylinders you can almost stand in. They burn this vile, dirty fuel that has to be heated before its viscosity is low enough for injection.

I've wondered how ships could be powered without fossil fuels. Perhaps someone will make fuel cells that oxidize metallic sodium? Ships could have honking great sodium tanks, since the stuff (like diesel fuel) is less dense than ater. The waste sodium oxide would be dispersed into the ocean, helping offset CO2-induced acidity.

[mmcirvin.livejournal.com]

Recent discoveries that you can change, at a very teeny scale, the properties of space-time in ways that influence chemical reactions

Cite?

(If this is supposed to be a general-relativistic effect, I say it's bullshit. If it's the Casimir effect or something, some kind of cavity effect on field modes, that's interesting but should probably be phrased differently.)

[fivemack.livejournal.com]

http://pipeline.corante.com/archives/2012/09/14/chemistry_in_the_quantum_vacuum_no_really.php is probably the popularisation that pointed at it; the underlying paper is at http://onlinelibrary.wiley.com/doi/10.1002/anie.201107033/abstract and, whilst the full text costs dozens of dollars, the graph indicates that the molecule indeed behaves differently when in a very small conducting cavity.

(though the discreteness of the point positions on the graph suggests that this is a very small signal being measured, you're seeing lines for log(n) at n=2 n=3 n=4 ...)

[resonant.livejournal.com]

I hadn't heard anything about that, but you CAN increase the energy content of some solid fuels by exposing them to gamma rays. Radiation polymer crosslinking lets you change the properties of materials in interesting ways, including increasing the enthalpy of the polymer.

[yorksranter.wordpress.com (from livejournal.com)]

Wow, the BBC piece-to-camera is astonishingly bafflegabby. It's made of air and water. And methanol. And "DME, an alternative to diesel".

[neowolf2.livejournal.com]

It's not hard to figure out what they're talking about. Either water is turned to hydrogen and oxygen, or CO2 to CO and oxygen, via electrochemical techniques. The resulting gas can be combined with more CO2 and/or water and thermally shifted to make syngas (CO + H2), which is converted to methanol over a copper catalyst. Methanol can be dehydrated to DME, which can be used in diesel engines or used as a propane substitute.

It's all much cheaper to get the syngas from coal or natural gas, though.

[yorksranter.wordpress.com (from livejournal.com)]

That I get, but you'll notice they didn't mention the water, the electrolysis, the thermal shift reaction, the syngas, the catalyst, or what the DME had to do with it.

[laetitia-apis.livejournal.com]

Coal is solidified air.

[kgbooklog.livejournal.com]

Today's xkcd is apropos.

[neowolf2.livejournal.com]

But it's wrong. At no point was the universe composed only of hydrogen.